A wavelength dispersive X-ray fluorescence spectrometer of the present invention includes: a position sensitive detector (10) configured to detect intensities of secondary X-rays (41) at different spectral angles, by using detection elements (7) corresponding to the secondary X-rays (41) at different spectral angles; a measured spectrum display unit (14) configured to display a relationship between a position, in an arrangement direction, of each detection element (7), and a detected intensity by the detection element (7), as a measured spectrum, on a display (15); a detection area setting unit (16) configured to be set a peak area and a background area; and a quantification unit (17) configured to calculate, as a net intensity, an intensity of the fluorescent X-rays to be measured, based on a peak intensity in the peak area, a background intensity in the background area, and a background correction coefficient, and to perform quantitative analysis.